The surface tillage layer structure of sloping farmland has a significant impact on rainfall-runoff distri-bution;however,the relationships between the Tillage Layer Depth(TLD)and surface-subsurface runoff,and the cou...The surface tillage layer structure of sloping farmland has a significant impact on rainfall-runoff distri-bution;however,the relationships between the Tillage Layer Depth(TLD)and surface-subsurface runoff,and the coupling effects of surface-subsurface runoff on soil erosion are still unclear.Thus,a set of laboratory experiments were conducted to reveal impacts of tillage layer depth(10,20 and 30 cm)on surface-subsurface runoff relationships,eroded sediment processes,and soil erosion pattern evolution under the long-duration(180 min)rainfall simulation tests.A deeper TLD mitigated soil erosion.When the TLD increased from 10 to 30 cm,the average surface runoff decreased by 13%,subsurface runoff increased by 5%,and soil loss rate decreased by 19 g m^(-2)min^(-1).The interaction between surface runoff and subsurface runoff,influenced by the tillage layer depth,significantly impacts soil erosion.Both surface runoff and subsurface runoff promoted soil erosion at shallow tillage layer depths(10 and 20 cm).Conversely,at TLD 30,the diversion effect of subsurface runoff on surface runoff was enhanced,which played a role in alleviating soil erosion.With the increase of TLD,the soil erosion pattern changed from rill erosion to sheet or splash erosion.During the interill erosion stage,soil loss primarily occurred in the early stage,wherein the Variation Ratio(VR)of soil loss rate and surface runoff coefficient ranged from 2.16 to 4.99.At the rill erosion stage,the VR was approximately 1.0,and the soil loss rate was 2.7-to 6.3-fold greater than that in the interrill erosion stage.These results increase understanding of the effects of TLD on the coupling relationship of surface-subsurface runoff,which is of great significance for allevi-ating slope farmland erosion.展开更多
This paper presents a physically-based integrated hydrologic model that can simulate the rain-fall-induced 2D surface water flow,3D variably saturated subsurface flow,upland soil erosion and transport,and contaminant ...This paper presents a physically-based integrated hydrologic model that can simulate the rain-fall-induced 2D surface water flow,3D variably saturated subsurface flow,upland soil erosion and transport,and contaminant transport in the surface-subsurface system of a watershed.The model couples surface and subsurface flows based on the assumption of continuity conditions of pressure head and exchange flux at the ground,considering infiltration and evapotranspiration.The upland rill/interrill soil erosion and transport are simulated using a non-equilibrium transport model.Contaminant transport in the integrated surface and subsurface domains is simulated using advection-diffusion equations with mass changes due to sediment sorption and desorption and exchanges between two domains due to infiltration,diffusion,and bed change.The model requires no special treatments at the interface of upland areas and streams and is suitable for wetland areas and agricultural watersheds with shallow streams.展开更多
Hydrological modeling,leveraging mathematical formulations to represent the hydrological cycle,is a pivotal tool in representing the spatiotemporal dynamics and distribution patterns inherent in hydrology.These models...Hydrological modeling,leveraging mathematical formulations to represent the hydrological cycle,is a pivotal tool in representing the spatiotemporal dynamics and distribution patterns inherent in hydrology.These models serve a dual purpose:they validate theoretical robustness and applicability via observational data and project future trends,thereby bridging the understanding and prediction of natural processes.In rapid advancements in computational methodologies and the continuous evolution of observational and experimental techniques,the development of numerical hydrological models based on physicallybased surface-subsurface process coupling have accelerated.Anchored in micro-scale conservation principles and physical equations,these models employ numerical techniques to integrate surface and subsurface hydrodynamics,thus replicating the macro-scale hydrological responses of watersheds.Numerical hydrological models have emerged as a leading and predominant trend in hydrological modeling due to their explicit representation of physical processes,heightened by their spatiotemporal resolution and reliance on interdisciplinary integration.This article focuses on the theoretical foundation of surface-subsurface numerical hydrological models.It includes a comparative and analytical discussion of leading numerical hydrological models,encompassing model architecture,numerical solution strategies,spatial representation,and coupling algorithms.Additionally,this paper contrasts these models with traditional hydrological models,thereby delineating the relative merits,drawbacks,and future directions of numerical hydrological modeling.展开更多
基金supported by the National Natural Science Foundation of China(42377336 and U22A20611)Jiangxi Water Conservancy Science and Technology Major Project(202426ZDKT06)Hunan Students innovation and entrepreneurship training program(S202310542106).
文摘The surface tillage layer structure of sloping farmland has a significant impact on rainfall-runoff distri-bution;however,the relationships between the Tillage Layer Depth(TLD)and surface-subsurface runoff,and the coupling effects of surface-subsurface runoff on soil erosion are still unclear.Thus,a set of laboratory experiments were conducted to reveal impacts of tillage layer depth(10,20 and 30 cm)on surface-subsurface runoff relationships,eroded sediment processes,and soil erosion pattern evolution under the long-duration(180 min)rainfall simulation tests.A deeper TLD mitigated soil erosion.When the TLD increased from 10 to 30 cm,the average surface runoff decreased by 13%,subsurface runoff increased by 5%,and soil loss rate decreased by 19 g m^(-2)min^(-1).The interaction between surface runoff and subsurface runoff,influenced by the tillage layer depth,significantly impacts soil erosion.Both surface runoff and subsurface runoff promoted soil erosion at shallow tillage layer depths(10 and 20 cm).Conversely,at TLD 30,the diversion effect of subsurface runoff on surface runoff was enhanced,which played a role in alleviating soil erosion.With the increase of TLD,the soil erosion pattern changed from rill erosion to sheet or splash erosion.During the interill erosion stage,soil loss primarily occurred in the early stage,wherein the Variation Ratio(VR)of soil loss rate and surface runoff coefficient ranged from 2.16 to 4.99.At the rill erosion stage,the VR was approximately 1.0,and the soil loss rate was 2.7-to 6.3-fold greater than that in the interrill erosion stage.These results increase understanding of the effects of TLD on the coupling relationship of surface-subsurface runoff,which is of great significance for allevi-ating slope farmland erosion.
基金Supported by the University of Mississippi and the USDA Agricultural Research Service
文摘This paper presents a physically-based integrated hydrologic model that can simulate the rain-fall-induced 2D surface water flow,3D variably saturated subsurface flow,upland soil erosion and transport,and contaminant transport in the surface-subsurface system of a watershed.The model couples surface and subsurface flows based on the assumption of continuity conditions of pressure head and exchange flux at the ground,considering infiltration and evapotranspiration.The upland rill/interrill soil erosion and transport are simulated using a non-equilibrium transport model.Contaminant transport in the integrated surface and subsurface domains is simulated using advection-diffusion equations with mass changes due to sediment sorption and desorption and exchanges between two domains due to infiltration,diffusion,and bed change.The model requires no special treatments at the interface of upland areas and streams and is suitable for wetland areas and agricultural watersheds with shallow streams.
基金supported by the National Natural Science Foundation of China(Grant Nos.41930759,42325502)the West Light Foundation of the Chinese Academy of Sciences(Grant No.xbzg-zdsys-202215)+2 种基金the Chinese Academy Sciences Talents Program,National Cryosphere Desert Data Centerthe Qinghai Key Laboratory of Disaster Prevention(Grant No.QFZ-2021-Z02)2023 First Batch of Science and Technology Plan Projects of Lanzhou City(Grant No.2023-1-49)。
文摘Hydrological modeling,leveraging mathematical formulations to represent the hydrological cycle,is a pivotal tool in representing the spatiotemporal dynamics and distribution patterns inherent in hydrology.These models serve a dual purpose:they validate theoretical robustness and applicability via observational data and project future trends,thereby bridging the understanding and prediction of natural processes.In rapid advancements in computational methodologies and the continuous evolution of observational and experimental techniques,the development of numerical hydrological models based on physicallybased surface-subsurface process coupling have accelerated.Anchored in micro-scale conservation principles and physical equations,these models employ numerical techniques to integrate surface and subsurface hydrodynamics,thus replicating the macro-scale hydrological responses of watersheds.Numerical hydrological models have emerged as a leading and predominant trend in hydrological modeling due to their explicit representation of physical processes,heightened by their spatiotemporal resolution and reliance on interdisciplinary integration.This article focuses on the theoretical foundation of surface-subsurface numerical hydrological models.It includes a comparative and analytical discussion of leading numerical hydrological models,encompassing model architecture,numerical solution strategies,spatial representation,and coupling algorithms.Additionally,this paper contrasts these models with traditional hydrological models,thereby delineating the relative merits,drawbacks,and future directions of numerical hydrological modeling.
